The invention stabilizes a target volume located in a body relative to external coordinates so that an irradiating beam stays on the target volume and alternatively stays away from the target volume, the beam being controlled relative to the external coordinates by a separate control system. The beam irradiating the body can be any energy beam such as particle beams, beams of various wavelengths of electromagnetic radiation, and beams of acoustic energy. The invention has an actuator sub-system which moves the body to counter movements of the target volume within the body with the actuator sub-system being driven by a control signal output from a data processor which processes signals from an imager which is not confounded by the beam irradiating the target volume and which images markers which are located in the body in a calibrated relationship to the target volume.
There are occasions when a process in a body is intended to have an effect only a target volume in the body and the target volume can move within the body such that the process misses the target volume. For example, when a cancerous tumor in a body is being treated with a photon beam, a particle beam or an acoustic beam, or by hyperthermia or cryotherapy and the position of the tumor changes in the body as a result of respiration, blood flow, gastric motions, and other causes, then the treatment can miss the tumor and harm adjacent tissue which otherwise would be protected.
These problems are well known and workers have long been seeking solutions. In order to compensate for motions of a target volume in a body those motions must be measured. The key problem in the cancer therapy case is that those motions must be measured in the presence of the high energy, high intensity photon and particle radiations typically used in cancer therapy. Though marker imaging systems and positioning systems are shown in prior art--such as by Allen in U.S. Pat. No. 4,945,914--there is no suggestion of a solution to this key problem in prior art.
The invention shown here is based on the discovery of apparatus and methods which can image markers located in a body in the presence of the high energy, high intensity radiations in order to generate fast and reliable control signals to drive an actuator sub-system which moves the body to counter motions of a target volume in the body and thus stabilize the position of the target volume relative to external coordinates. This discovery is not suggested in prior art nor in any combinations of prior art and thus there is no suggestion of a system which images markers located in a body and moves the body to stabilize the position of a target volume in the body in prior art nor in any combinations of prior art.